UNIVERSITY  OF  CALIFORNIA  PUBLICATIONS. 


COLLEGE  OF  AGRICULTURE. 


AGRICULTURAL    EXPERIMENT    STATION. 


STUDIES   IN  GRASSHOPPER    CONTROL 


By  J.  S.  HUNTER. 


Small  Orchard  and  Vineyard  Defoliated  by  Grasshoppers. 


BULLETIN    No.    170. 

(Berkeley,  June,  1905.) 


SACRAMENTO: 
w.  w.  shannon,     :     :     :     :     superintendent  state  printing. 

1905. 


BENJAMIN  IDE  WHEELER,  Ph.D..  LL.D.,  President  of  the  University. 

EXPERIMENT  STATION  STAFF. 

E.  W.  HILGARD,  Ph.D.,  LL.D.,  Director  and  Chemist.     (Absent  on  leave.) 

E.J-  WICKSON,  M. A.,  Acting  Director  and  Horticulturist. 

W.  A.  SETCHELL,  Ph.D.,  Botanist. 

ELWOOD  MEAD,  M.S.,  C.E  ,  Irrigation  Engineer. 

C.  W.  WOODWORTH,  M.S.,  Entomologist. 

R.  H.  LOUGHRIDGE,  Ph.D.,  Agricultural  Geologist  and  Soil  Physicist.     (Soils  and  Alkali.) 

M.  E.  JAFFA,  M.S.,  Assistant  Chemist.     (Foods.  Nutrition.) 

G.  W.  SHAW,  M.A.,  Ph.D.,  Assistant  Chemist.     (Starches,  Oils,  Beet-Sugar.) 

GEORGE  E.  COLBY,  M.S.,  Assistant  Chemist.     (Fruits,  Waters,  Insecticides.) 

RALPH  E-  SMITH,  B.S.,  Plant  Pathologist. 

A.  R.  WARD,  B.S.A.,  D.V.M.,  Veterinarian  and  Bacteriologist. 

E.  W.  MAJOR,  B.Agr.,  Animal  Industry. 

A.  V.  STUBENRAUCH,  M.S.,  Assistant  Horticulturist,  in  charge  of  Substations. 

E.  H.  TWIGHT,  B.Sc,  Diplome  E.A.M.,  Viticulturist. 

F.  T.  BIOLETTI,  M  S  ,  Viticulturist. 

WARREN  T.  CLARKE,  B.S.,  Assistant  Field  Entomologist. 
H.  M.  HALL,  M.S  ,  Assistant  Botanist. 

,  Assistant  Entomologist. 

GEORGE  ROBERTS,  M.S.,  Assistant  Chemist,  in  charge  of  Fertilizer  Control. 
C.  M    HARING,  D.V.  M.,  Assistant  Veterinarian  and  Bacteriologist. 
C.  A.  COLMORE,  B.S  ,  Clerk  to  the  Director. 


R.  E-  MANSELL.  Foreman  of  Central  Station  Grounds. 

JOHN  TUOHY.  Patron,     ) 

-    Tulare  Substation,  Tulare. 
,  Foreman,        ) 


\  Southern  California  Substation. 


J.  E   McCOMAS,  Patron,  Pomona, 

J.  W.  MILLS,  Superintendent,  Poniona, 

In  charge  Cooperation  Experiments  in  Southern  California, 

,  Assistant  Superintendent,  Ontario, 

J.  W.  ROPER,  Patron,  ) 

V    University  Forestry  Station,  Chico. 
HENRY  WIGHTMAN,  In  charge,       ) 

ROY  JONES,  Patron,      ) 

[-    University  Forestry  Station,  Santa  Monica. 
-,  Foreman,    ) 

VINCENT  J    HUNTLEY,  Foreman  of  California  Poultry  Experiment  Station,  Petaluma. 


The  Station  publications  (Reports  and  Bulletins),  so  long  as  avail- 
able, will  be  sent  to  any  citizen  of  the  State  on  application. 


STUDIES  IN  GRASSHOPPER  CONTROL 


By  J.  S.  HUNTER. 


Introductory  Note. — The  present  bulletin  presents  some  of  the  results  obtained  in  a 
rather  extensive  and  quite  successful  effort  to  prevent  grasshopper  injury.  The  work 
was  started  by  myself  in  1903,  with  the  assistance  of  Mr.  William  La  Grange,  a  student  in 
the  department;  but  the  success  of  the  practical  work  has  been  largely  due  to  Mr.  J.  S. 
Hunter,  whose  energy  and  persistence  through  the  campaign  of  1904  has  not  only 
resulted  in  the  prevention  of  extensive  injury  during  that  season,  but  has  also  taught 
the  ranchers  in  the  affected  section  so  well  that  serious  damage  will  probably  not  be 
permitted  to  occur  again  in  that  region. 

The  work  was  rendered  possible  through  the  hearty  cooperation  of  the  people   of 

that  section,  and  I  wish  particularly  to  mention  the  financial  support  afforded  us  by  the 

firm  of  Hultberg  &  Soderberg,  of  Turlock,  and  the  personal  interest  of  their  manager, 

Mr.  Hallmer. 

C.  W.  WOODWORTH. 

During  the  summer  of  1904  grasshoppers  did  extensive  damage  in 
several  sections  of  the  San  Joaquin  Valley.  Perhaps  the  most  seriously 
infested  region  was  in  Merced  County,  where  a  great  deal  of  injury  was 
done.  The  two-  localities  particularly  infested  with  the  insects  were  a 
district  bordering  on  Stanislaus  County,  south  of  Turlock,  and  the 
country  immediately  south  of  Newman. 

Grasshoppers  began  to  be  observed  at  Turlock  early  in  May.  The 
insects  had  done  considerable  damage  in  this  region  during  the  previous 
summer,  and  an  attempt  had  been  made  by  the  University  to  locate 
accurately  and  stake  out  the  breeding  grounds,  in  order  that  they  might 
be  plowed  by  the  ranchers  during  the  following  fall  or  winter,  or  at 
least  to  afford  a  knowledge  of  the  places  most  liable  to  be  affected  this 
year.  The  breeding  grounds  were  not  plowed,  nor  were  they  watched 
in  the  early  spring  for  the  purpose  of  attacking  the  young  grasshoppers 
as  early  as  possible  after  they  emerge  from  the  eggs.  They  appeared  in 
much  greater  numbers  than  in  1903.  Hatching  must  have  occurred  in 
April  or  earlier,  for  when  we  were  notified  in  the  middle  of  May  the 
grasshoppers  were  almost  grown  and  threatened  to  devastate  the  country. 
At  the  very  urgent  request  of  the  people  of  the  Hilmar  Colony,  the 
writer  was  sent  to  superintend  a  campaign  against  the  grasshoppers  in 
that  district. 

In  order  to  explain  the  situation  thoroughly  a  brief  description  of  the 
infested  regions  may  be  necessary.  At  Turlock  grasshoppers  first  began 
to  do  damage  in  what  is  known  as  the  Hilmar  Colony,  comprising  some 
six  or  seven  thousand  acres.  Formerly  this  land  was  all  planted  to 
wheat  and  rye,  but  for  a  number  of  years  previous  to  being  colonized 
in  1902  it  had  been  left  idle,  so  that  it   had  approximately  reverted 


4  UNIVERSITY    OF    CALIFORNIA  — EXPERIMENT   STATION. 

to  its  original  condition.  At  present  about  half  the  land  is  under 
cultivation,  being  for  the  most  part  planted  to  young  orchards,  vine- 
yards, alfalfa,  and  ordinary  field  crops.  In  many  cases  these  cultivated 
places  are  surrounded  by  uncultivated  fields.  It  was  in  this  idle  land 
that  the  grasshoppers  of  the  previous  year  had  deposited  their  eggs, 
and  consequently  it  was  here  that  they  first  were  noticed,  moving 
afterwards  on  to  the  green  crops  in  the  cultivated  portions. 

At  Newman  the  grasshopper-infested  district  on  the  other  hand  is, 
so  to  speak,  one  large  alfalfa  field,  which  is  divided  into  smaller  ranches. 
The  grasshoppers  were  more  or  less  numerous  on  about  two  or  three 
thousand  acres. 

The  grasshoppers  in  this  region  began  to  work  during  May,  but  were 
not  regarded  as  a  serious  matter  by  the  ranchers  until  a  month  later, 


Fig.  1.    Long-legged  Grasshopper  (Clinopleura  melanopleura),  female.    Notice  long  ovipositor. 

about  the  first  of  July,  when  the  University  was  appealed  to  for  aid, 
since  the  losses  had  become  so  evident  that  the  ranchers  were  thoroughly 
aroused. 

There  were  two  species  of  grasshoppers  that  did  the  greater  part  of 
the  injury,  and  four  other  species  that  were  abundant  enough  to  con- 
tribute materially  to  the  losses  sustained.  Other  species  were  also 
present,  but  not  in  sufficiently  large  numbers.  Several  of  these  might, 
however,  under  favorable  conditions,  become  as  troublesome  as  those 
discussed  in  this  bulletin. 

The  Long-legged  Grasshopper  (Clinopleura  melanopleura),  Figs.  1  and 
2,  the  least  injurious  of  the  four  species,  is  a  katydid.  This  species  was 
found  at  Turlock,  and  in  some  parts  of  the  colony  was  very  common, 
but  still  not  numerous  enough  on  any  cultivated  portion  to  do  damage 
had  the  species  been  alone,  but  it  did  augment,  quite  appreciably,  the 
loss  occasioned  by  the  more  prevalent  grasshoppers. 


STUDIES   IN    GRASSHOPPER    CONTROL. 


The  Pale-winged  Grasshopper  (Melanoplus  uniformis),  Fig.  3. — This 
species  was,  during  the  summer  of  1903,  the  most  troublesome  kind  in 
the  region  southeast  of  Turlock.  It 
was  the  first  species  to  be  noticed  fly- 
ing in  any  considerable  number,  and 
the  only  truly  migratory  grasshopper 
that  was  found  at  either  Turlock  or 
Newman.  It  is  a  rather  restless  species 
after  becoming  winged,  and  as  a  rule 
did  not  remain  in  any  one  spot  long 
enough  to  do  any  perceptible  damage. 
A  considerable  swarm  has  been  ob- 
served feeding  on  a  field  of. alfalfa 
during  a  month  without  apparently 
injuring  the  crop. 

The  first  movement  of  this  species 
was  noticed  after  a  high  northwest 
wind  on  June  2d  and  3d.  Many 
swarms  of  grasshoppers  were  seen 
flying,  for  the  most  part,  in  a  north- 
easterly direction.  Swarms  of  grass- 
hoppers at  this  time  came  on  to  land 
that  previously  had  been  free.  After 
this  for  a  month,  during  the  last  hours 
of  the  day  and  when  the  wind  was 
not  blowing  hard,  grasshoppers  could 
be  seen  moving  toward  the  northeast.  Toward  the  middle  of  July  the 
flight  seemed  to  be  in  a  northwesterly  direction.  At  no  time,  however, 
was  there  another  as  general  a  movement  as  the  one  that  occurred  on 

June  5th.  During  the  latter 
part  of  September  a  swarm  of 
grasshoppers  that  had  estab- 
lished themselves  on  a  large 
idle  field  northwest  of  Turlock 
took  wing  and  flew  rather  low 
over  the  town  in  a  south- 
easterly direction. 

This  species  seemed  to  be 
rather  slow  in  coming  to  full 
maturity;  pairing  was  not  ob- 
served previous  to  the  middle 
of  August.     Egg-laying  was  under  way  by  the  first  week  in  October,  and 
at  that  time  nearly  all  the  females  contained  well-developed  eggs. 

The  Devastating  Grasshopper  (Melanoplus  devastator). — Late  in  June 
grasshoppers  were  reported  as  doing  extensive  damage  in  the  foothill 


Fig. 


2.     Long-legged  Grasshopper    (Clino- 
pleura  melanopleura) ,  male. 


Fig.  3. 


Pale-winged  Grasshopper  (Melanoplus 
uniformis),  male. 


6 


UNIVERSITY    OF    CALIFORNIA— EXPERIMENT   STATION. 


region  below  Mariposa.  It  was  thought  best  to  make  a  trip  through 
that  region  and  learn,  if  possible,  what  danger  there  was  of  the  grass- 
hoppers moving  down  into  the  valley.  The  territory  from  Snelling  to 
Raymond  and  from  White  Rock  to  as  high  as  Wawona  was  thoroughly 
gone  over.  Grasshoppers  were  found  more  or  less  over  the  entire 
region,  but  only  in  certain  sections  were  particularly  abundant.  The 
species  M.  devastator  is  a  true  foothill  species  and  has  often  developed 
migratory  habits.  Egg-laying,  as  a  rule,  is  done  almost  exclusively  in 
the  foothills.  According  to  the  reports,  about  once  in  seven  to  nine 
years  they  become  so  numerous  that  all  the  cultivated  land  in  the  foot- 
hills will  be  stripped,  sometimes  even  taking  the  leaves  from  the  oak 
trees.  At  such  times  there  is  danger  of  their  moving  into  the  valley. 
In  1904  they  were  nowhere  near  as  thick  as  they  had  been  in  years  past. 
None  of  the  methods  that  are  practical  in  the  control  of  the  grass- 
hoppers in  the  lower  valley  seem  to  be  very  much  so  in  the  foothills. 
Burning  is  about  the  only  method  that  can  be  used.  If  the  grass- 
hoppers are  confined  to  a 
small  area  and  a  sufficient 
force  of  men  is  obtained  so 
that  the  fire  can  be  kept 
under  control,  it  will  of 
course  destroy  the  insects. 
A  fire  once  beyond  control, 
however,  will  sweep  over 
valuable  pasture  lands  and 
might  work  up  into  the  still 
more  valuable  timber  lands 
farther  up  in  the  hills. 
Poisoning  is  hardly  to  be  considered  in  the  breeding-grounds,  because 
of  the  large  area  to  be  covered,  but  might  be  useful  in  the  smali  culti- 
vated portion,  though  even  there  the  grasshoppers  may  work  in  from 
the  outside  in  such  large  numbers  that  all  vegetation  will  be  destroyed. 
The  grass  on  the  ranges  is  seldom  permanently  injured  by  the  work 
of  the  grasshoppers,  the  loss  in  this  region  being  confined  to  the  few 
fruit  trees  around  the  ranch  houses  and  to  garden  spots.  In  some  cases 
this  year  these  gardens  had  been  most  thoroughly  cleaned  out.  One 
patch  of  corn  was  seen  where  nothing  was  left  but  the  hard  outside  por- 
tion of  the  stalk,  the  pith  even  being  excavated  by  the  insects. 

Hesperotettix  Sp. — This  species,  which  was  rather  abundant  at  New- 
man, is  much  smaller  than  the  dominant  form  and  is  dark  brown  in 
color.  The  males  are  very  short-winged,  the  wings  not  reaching  half 
way  to  the  end  of  the  body.  The  females  are  much  longer-winged. 
Although  rather  abundant,  the  damage  done  could  scarcely  be  noticed 
alongside  of  that  done  by  the  larger  M.  differ entialis.  The  species,  on 
account  of  its  short  wings,  is  easily  caught  in  the  dozer.     Pairing  was 


Fig.  4.    Valley  Grasshopper  (<Edaleoiwtns  enigma). 


STUDIES   IN    GRASSHOPPER    CONTROL. 


under  way  during  the  latter  part  of  June.  Those  noticed  laying  eggs 
did  not  do  so  in  the  ordinary  manner,  the  hole,  on  account  of  the  size 
of  the  species,  not  being  very  deep  and  for  the  most  part  drilled  straight 
into  the  ground. 

The  Valley  Grasshopper  {(Edaleonotus  enigma),  Figs.  4  and  5. — This 
species  was  by  far  the  most  destructive  at  Turlock,  causing  fully  ninety 
per  cent  of  the  losses.  It  was  present  throughout  the  entire  Turlock  dis- 
trict, being  most  numerous  in  the  Hilmar  Colony.  Both  the  short-  and 
the  long-winged  forms  were  noted,  the  former  being  the  more  common. 
There  was  some  migration  in  the  case  of  the  long-winged  form  of  this 
species,  but  not  so  much  as  for  M.  uniformis.  The  species  reached 
maturity  about  June  1st.  Pairing  was  first  noted  on  June  2d,  but  it  was 
not  until  the  24th  of  the  same  month  that  eggs  were  found,  on  dissection, 
large  enough  to  be  laid.  Up  to  the  middle  of  August,  however,  although 
careful  watch  was  kept,  no  grasshoppers  were 
found  laying  eggs,  but  on  a  trip  to  the  region 
in  the  early  part  of  October,  both  this  species 
and  M.  uniformis  were  found  laying  in  con- 
siderable numbers  in  certain  fields. 

The  egg-laying  is  not  greatly  different  from 
that  of  most  other  species  of  grasshoppers. 
With  the  four  hard  horny  points  on  the  end 
of  the  abdomen,  the  female  drills  a  hole  in  the 
ground  about  half  an  inch  deep.  She  then 
ejects  a  small  amount  of  a  white,  frothy  paste, 
and  then  places  the  eggs  in  regular  order  hori- 
zontally until  all  of  the  developed  eggs  in  the 
oviduct  are  deposited.  With  each  successive 
layer  she  ejects  more  of  the  same  frothy  sub- 
stance, which  soon  hardens,  forming  an  almost 
waterproof  capsule  around  each  egg-mass  and 
cementing  the  eggs  firmly  together.  More  of  this  substance  is  used  for 
rilling  the  hole.  She  then  draws,  with  the  end  of  the  abdomen,  small 
grains  of  dirt  over  the  hole,  covering  it  so  securely  that  even  with  the 
closest  observation  it  can  seldom  be  found.  The  places  usually  chosen 
for  egg-laying  are  those  thinly  covered  with  vegetation  and  where  the 
ground  is  rather  firm — the  most  compact  soil,  indeed,  found  in  the 
region ;  but  the  Turlock  soil  is  for  the  most  part  comparatively  loose 
and  sandy.  The  full  complement  of  eggs  is  usually  placed  in  one  hole. 
This  will  be  normally  about  twenty-five. 

The  egg-laying  of  the  previous  species  is  almost  identical  with  that  of 
0.  enigma,  but  perhaps  with  greater  care  taken  in  concealing  the  hole. 
Both  species  are  easily  disturbed  when  laying,  and  will  quickly  jump 
or  fly  from  the  hole. 


Fig    5.     Valley  Grasshopper. 
{(Edaleonotus  en  igma). 


8 


UNIVERSITY    OP    CALIFORNIA— EXPERIMENT    STATION. 


THE    CAMPAIGN    AT    TURLOCK. 

Burning  the  Young  Grasshoppers.- — During  the  first  few  weeks  of  the 
work  against  the  grasshoppers  the  method  of  destruction  employed  was 
that  of  fire.  This  we  found  could  be  effectively  used  only  on  land  that 
had  considerable  grass.  The  greater  part  of  the  grass  and  weeds  at 
that  time  of  the  year  is  dry  enough  to  burn  freely,  but  a  great  deal  of  the 
land  affected  by  grasshoppers  was  rather  bare.  When  the  fire  travels 
fast  everything  is  swept  before  it,  the  grasshoppers  being  killed  before 
they  hardly  have  time  to  leap.  When  the  fire  progresses  slowly  they 
may  at  first  jump  about  confusedly  ahead  of  the  fire;  and  when  the  fire 


Fig.  6.   The  preparation  of  the  "  firing  line." 

comes  near  them,  they  become  bewildered  and  attempt  to  hide  in  the 
grass..  Some  may  occasionally  escape  by  crawling  into  holes  in  the 
ground,  others  by  hiding  in  a  patch  of  weeds  too  green  to  burn.  For 
the  most  part,  however,  until  large  enough  to  fly,  the  flames  destroy  at 
least  ninety  per  cent  of  the  hoppers. 

Burning  the  Winged  Form. — After  nearly  three  thousand  acres  of 
land  had  been  burned  the  grasshoppers  on  unburned  land  had  devel- 
oped wings.  These  enabled  so  many  of  them  to  escape  the  flames  that 
it  was  considered  useless,  except  under  unusual  conditions,  to  depend 
on  burning.     The  best  results  then  seemed  to  come  from  night  work. 

The  nights  being  cool,  the  grasshoppers  were  not  as  active  as  during 
the  day  and  many  more  were  caught  by  the  flames,  but  still  the  work 


STUDIES   IN    GRASSHOPPER    CONTROL 


9 


was  not  as  successful  as  during  the  nymph  stage.  Enough  were  killed, 
however,  to  amply  pay  for  the  trouble  of  burning  the  grass.  Unusually 
oool  and  windy  nights  were  found  to  be  the  best.  Under  these  condi- 
tions the  grasshoppers  were  less  active,  and  with  the  flames  sweeping 
rapidly  across  a  field  most  of  the  grasshoppers  would  be  caught.  The 
most  successful  results  were  obtained  by  firing  from  both  sides  of  the 
field.  Where  the  insects  were  thick  a  line  of  dead  grasshoppers  could 
be  distinctly  seen  where  two  such  fires  came  together. 

Burning  was  more  successful  with  0.  enigma  than  with  M.  uniformis, 
the  former  not  being  as  active.  That  species  could  possibly  also  be 
destroyed  more  effectively  by  burning   later  in   the   season  than  at  an 


Fig.  7.    Burned  area  on  the  right,  showing  control  of  fire  by  "  firing  line." 

earlier  date,  on  account  of  the  fact  that  the  wings  become  frayed  out 
and  the  bodies  heavier,  so  that  the  grasshoppers  would  be  less  able  to 
fly  out  of  the  flames. 

Burning  is  to  be  recommended  only  where  the  pasture  burned  over  is 
of  no  great  value  and  where  the  grasshoppers  are  seriously  threatening 
orchards  or  other  cultivated  fields.  Care  will  always  have  to  be  taken 
that  the  fire  is  kept  under  perfect  control,  as  any  damage  resulting  can 
be  charged  to  the  person  starting  the  fire. 

Poisoning  the  Grasshoppers. — After  burning  was  done,  the  grasshop- 
pers that  escaped  moved  into  cultivated  fields.  These  fields  may  be 
divided  into  two  classes;  alfalfa  and  other  field  crops  forming  one  class, 
and  orchards  and  vineyards  the  other. 

The  most  successful  means  of  fighting  grasshoppers  in  orchards  and 


10  UNIVERSITY   OF    CALIFORNIA  — EXPERIMENT    STATION. 

vineyards  was  by  poisoned  bait.  The  "  Criddle  mixture, "  recently 
highly  recommended  in  the  East,  did  not  prove  very  satisfactory.  The 
formula  is  as  follows:  100  pounds  of  horse  dung,  1  pound  of  paris 
green  or  powdered  arsenic,  and  2  pounds  of  salt,  adding  enough  water  to 
moisten  but  not  make  soggy.  The  failure  of  this  mixture  was  because 
very  few  of  the  grasshoppers  were  found  to  eat  it  at  all.  This  may  be 
attributed  to  the  fact  that  under  the  dry  condition  of  the  interior  valleys 
the  mixture  would  dry  out  too  rapidly.  At  any  rate,  it  did  not  seem 
to  have  any  power  of  attracting  the  grasshoppers.  Probably  later  in 
the  season  this  formula  might  have  been  used  more  successfully,  judging 
from  the  fact  that,  although  early  in  the  summer  very  few  grasshoppers 
were  seen  on  the  piles  of  horse-droppings  along  the  roads,  later  in  the 
year  such  piles  would  be  covered  with  the  hungry  insects.  The  mix- 
ture can  not  be  recommended  except  where  the  grasshoppers  are  observed 
to  be  attracted  by  horse-droppings. 

Far  different  was  the  experience  with  the  formula  of  grasshopper 
poison  that  has  been  used  so  many  years  in  various  parts  of  California. 
The  proportions  used  were: 

Bran 40  pounds 

Molasses  (cheap) .. 2  gallon- 
Arsenic 5  pounds 

The  above  amounts  of  material  will  be  enough  to  fill  a  good-sized 
tub.  It  will  be  found  easier  to  mix  only  .half  the  given  amounts  at  a 
time.  The  stronger  'smelling  molasses  used  seemed  to  be  the  more 
attractive  to  the  grasshoppers.  In  a  number  of  cases  where  molasses 
could  not  be  obtained,  black  honey  was  tried,  but  it  did  not  seem  to  be 
as  good  as  the  molasses  for  attracting  the  insects.  Paris  green  can  be 
used  in  place  of  arsenic,  but  the  latter  is  considerably  cheaper,  costing^ 
in  quantities,  less  than  ten  cents  a  pound. 

In  order  to  get  the  best  results  from  the  bait,  considerable  care  must 
be  taken  in  mixing  it.  It  was  found  most  successful  to  mix  the  bran 
with  enough  water  that  a  lump  held  in  the  hand  will  only  slightly 
drip  unless  squeezed.  The  molasses  can  then  be  added,  mixing  it  thor- 
oughly with  the  hands.  After  this  has  been  well  done,  the  arsenic 
can  be  added.  This  can  be  worked  into  the  bran  with  the  hands  or 
with  a  paddle.  There  may  be  some  danger  in  using  the  hands  to  mix 
this  poison  if  there  are  cuts  or  sores,  and  care  should  be  taken  in 
removing  any  arsenic  that  may  have  lodged  around  the  finger  nails. 

Another  method  is  to  mix  the  arsenic  and  bran  in  a  barrel  with  a 
shovel,  or  in  a  mortar-bed  with  a  hoe;  then  dilute  the  molasses  with 
water  and  work  it  in  as  in  mixing  mortar.  In  any  case,  mix  it  thor- 
oughly. It  is  a  good  plan  to  let  the  material  stand  from  twelve  to 
twenty-four  hours,  then  remix  it,  so  as  to  allow  the  arsenic  that  is 
dissolved  to  soak  well  into  the  bran. 


STUDIES    IN    GRASSHOPPER    CONTROL.  11 

The  usual  practice  is  to  place  as  much  poisoned  bait  as  can  be  held 
in  a  soup-spoon  in  a  pile  on  the  ground;  or,  perhaps  better,  on  a  shingle 
at  the  base  of  each  tree  or  vine.  If  the  grasshoppers  are  coming  into 
the  orchard  from  one  side  only,  poison  need  only  be  placed  along  the 
first  six  or  eight  rows  of  trees.  It  was  found  very  effective  in  such  cases 
to  place  a  series  of  piles  of  poison,  about  a  foot  apart,  along  the  threat- 
ened side.  As  soon  as  the  poison  is  dry  it  should  be  moistened,  as  the 
grasshoppers  will  not  eat  much  of  it  when  it  is  dry..  In  our  experi- 
ments it  was  found  that  when  properly  mixed,  the  bait  was  evidently 
preferred  to  the  foliage  of  fruit  trees.  The  placing  of  the  poison  on 
a  board  is  recommended  in  order  that  it  may  be  gathered  up  after 
the  danger  from  grasshoppers  is  over.  Serious  results  to  stock  may 
accrue  if  the  poison  is  left  in  the  field  and  cattle  be  allowed  to  get 
hold  of  it. 

In  some  cases  the  poison  was  scattered  broadcast  over  the  orchard, 
but  the  results  obtained  were  by  no  means  as  satisfactory  as  from  the 
other  method.  The  poison  in  such  cases  dried  quicker  and  afterwards 
could  not  be  remoistened  conveniently. 

When  grasshoppers  are  gathered  in  bunches,  as  along  irrigation 
ditches,  they  can  be  poisoned  by  the  thousand.  A  striking  illustration 
of  the  immediate  effectiveness  of  the  poison  occurred  in  a  large  pasture. 
There  the  grasshoppers  had  bunched  in  the  shade  of  six  or  eight  locust 
trees  around  an  old,  deserted  ranch  house,  and  when  first  found,  they 
covered  the  ground  and  were  crawling  up  the  trunks  of  the  trees 
by  thousands  to  get  the  green  leaves.  Poison  was  put  out,  and  on  the 
following  day  fully  seventy-five  per  cent  of  the  swarm  were  dead,  and 
a  few  days  later  scarcely  a  live  grasshopper  could  be  found.  In  places 
the  ground  was  completely  covered  by  dead  grasshoppers. 

While  live  stock,  and  especially  chickens,  are  very  liable  to  be  poi- 
soned if  they  are  allowed  to  have  access  to  the  grasshopper  poison, 
there  seems  to  be  very  little  danger  of  poisoning  beneficial  wild  birds; 
for  careful  watch  was  kept  while  the  poison  was  out  for  any  that  might 
have  got  hold  of  either  the  poison  or  the  dead  grasshoppers,  and  not  a 
single  dead  bird  was  found. 

Effect  of  Poison  on  the  Grasshopper. — When  the  grasshoppers  are 
hungry,  as  they  are  when  they  come  in  from  the  dry  pastures,  they 
very  greedily  eat  the  bran.  In  some  cases  they  piled  up  on  the  poison 
so  that  nothing  could  be  seen  but  a  mass  of  struggling,  kicking  insects. 

After  eating  until  gorged,  the  grasshopper  crawls  slowly  away,  hunt- 
ing a  shady  spot.  There  it  remains  quiet  until  the  effect  of  the  poison 
becomes  more  acute;  then  a  twitching  or  kicking  of  the  rear  legs  will 
be  noticed.  These  convulsions  become  quite  violent  in  some  cases;  in 
others,  there  will  be  none  at  all.  It  is  usually  from  eight  to  ten  hours 
before  any  dead  will  be  noticed.     Afterwards  they  die  slowly  for  about 


12  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT    STATION. 

eight  hours  more;  from  eighteen  to  twenty-four  hours  the  greatest  death- 
rate  occurs.  As  soon  as  grasshoppers  begin  to  die,  the  ones  that  have  not 
yet  eaten  poison  will  begin  to  eat  the  dead  ones.  Numbers  will  be 
killed  in  this  manner,  but  it  is  not  known  for  how  many  successive 
individuals  it  will  be  effective.  In  orchards  wThere  clean  cultivation  is 
practiced,  the  poison  is  more  effective  than  in  those  where  weeds  are 
allowed  to  grow.  All  species  of  grasshoppers  do  not  take  the  poison 
as  freely  as  0.  enigma.  M.  uniformis  is  one  of  these.  As  a  rule,  the 
more  active  the  grasshoppers,  the  less  likely  are  they  to  take  the  poison. 

If  grasshoppers  come  into  the  orchard  in  such  numbers  that  they 
must  be  taken  care  of  at  once,  more  active  and  quicker  methods  of 
protecting  the  trees  must  be  employed. 

The  use  of  the  hopper  dozer  is  not  as  effective  in  the  orchard  as 
in  the  alfalfa  fields.  In  fact,  when  the  grasshoppers  are  on  the  trees 
and  not  on  the  ground,  not  enough  will  be  caught  to  pay  for  running 
the  dozer.  In  vineyards  a  dozer  can  be  used  more  successfully.  The 
use  and  construction  of  the  hopper  dozer  is  given  later  in  this  bulletin 
under  a  different  heading. 

In  young  orchards,  two  or  three  years  old,  it  is  a  very  good  plan  to 
wrap  the  trunks  of  the  trees  with  strips  of  cloth.  This  not  only  protects 
the  bark  from  grasshoppers,  but,  in  case  the  leaves  are  eaten,  it  prevents 
the  bark  from  becoming  sunburned.  If  it  is  only  a  drifting  swarm  that 
temporarily  threatens  the  orchard,  and  the  trees  are  not  too  large  or  too 
many,  they  can  be  covered  with  sacks  of  burlap  or  other  cloth.  It  will 
be  necessary  to  tie  the  sacks  securely  around  the  trunks  and  leave  no 
holes  large  enough  for  grasshoppers  to  crawl  through,  or  they  will  get 
inside  and  badly  injure  the  tree.  These  sacks  can  not  usually  be  left 
for  any  great  length  of  time,  or  the  tree  will  be  weakened.  However, 
some  small  orchards  at  Turlock  that  were  covered  for  a  month  or  longer 
came  through  very  nicely.  Yearling  vines  were  saved  in  some  cases  by 
turning  the  soil  over  them  with  a  cultivator.  In  such  cases  the  soil 
must  be  taken  away  as  soon  as  the  danger  is  past.  Even  then  the  vines 
may  be  killed. 

Smoking  the  Grasshoppers. — The  two  species  of  grasshoppers  common 
to  Turlock  can  be  smoked  or  smudged  out.  Very  good  results  were 
obtained  by  placing  piles  of  rather  damp  manure  on  the  windward  side 
of  the  orchard  and  other  piles  in  rows,  a  hundred  yards  apart,  through 
the  orchard.  This  manure,  when  burning,  gives  off  a  dense  smoke, 
which  is  not  liked  by  most  species  of  grasshoppers.  When  once  on  the 
wing,  they  will  keep  on  flying  until  entirely  out  of  the  smoke.  It  was 
found  more  satisfactory  to  go  through  the  orchard  after  the  smudges  were 
started  and  shake  the  trees,  forcing  the  grasshoppers  to  take  wing. 
Smoking  as  long  as  the  grasshoppers  threaten  the  orchard  proved  very 


STUDIES   IN    GRASSHOPPER    CONTROL. 


13 


successful  in  numerous  cases.  During  cool  nights  smoking  was  not  suc- 
cessful, nor  was  it  as  a  rule  successful  early  in  the  forenoon  or  late  in 
the  afternoon. 

Crude  oil  makes  a  very  good  smoke,  but  under  usual  conditions  is  too 
expensive  to  be  used  extensively.  Any  substance  that  will  make  a  good 
pungent  smoke  will  be  satisfactory.  A  small  quantity  of  sulfur  may 
be  put  on  the  fire,  but  there  is  considerable  danger  of  causing  the  leaves 
to  drop  from  the  trees  if  the  fires  are  too  close  or  too  much  sulfur  is 
used. 

Smoking  was  most  successful  when  there  was  a  rather  stiff  breeze 
blowing,  so  as  to  keep  the  smoke  close  to  the  ground.  In  connection 
with  the  smoke,  one  very  good  way  of  trapping  the  grasshoppers  was 
by  putting  rows  of  straw,  sprinkled  with  water  sweetened  with  strong 
molasses,  on  the  leeward  side  of  the  orchard.     Many  of  the  grasshop- 


Fig.  8.    Hopper  dozer  with  strainer  to  save  the  oil  removed  from  the  pans  when  the 

grasshoppers  are  shoveled  out. 

pers,  on  coming  to  this  straw,  will  take  refuge  in  it,  being  attracted  by 
the  molasses  odor.  Later  in  the  day,  when  they  become  less  active, 
this  straw  can  be  burned.  The  same  method  can  be  used  when  grass- 
hoppers are  coming  into  a  field  from  an  adjoining  one.  In  some  cases 
they  will  gather  on  the  straw  in  sufficient  numbers  to  cover  it. 

Sometimes  the  grasshoppers  come  in  so  persistently  that  more 
extreme  methods  must  be  used  in  order  to  save  the  trees.  One  farmer, 
in  addition  to  poison,  smoke,  dozers,  and  other  methods,  had  his  entire 
family  turn  out  before  daylight  in  the  morning  to  kill  the  grasshoppers 
on  the  trees.  On  account  of  his  energy  and  persistence,  he  lost  very 
few  trees  from  the  pest.  His  place  was  one  around  which  the  grass- 
hoppers were  thicker  and  more  persistent  than  around  any  other  farm 
in  the  locality. 

Unless  the  trimming  done  by  the  grasshoppers  is  too  severe,  it  results 
only  in  the  setting  back  of  the  trees  for  that  year.  If  the  leaves  and 
bark  are  stripped  from  the  limbs,  the    tree  will    usually  die.     In  all 


14  UNIVERSITY    OF    CALIFORNIA  — EXPERIMENT    STATION. 

cases  after  the  grasshoppers  had  stripped  the  trees,  it  was  found  best  to 
irrigate  them  as  soon  as  Avater  could  be  obtained.  In  a  number  of 
cases,  although  the  trees  were  very  severely  trimmed,  they  put  out  new 
leaves  and  quite  a  growth  was  made  before  fall.  Vines,  for  the  most 
part,  stand  the  severe  treatment  much  more  successfully  than  trees, 
provided  they  are  not  allowed  to  suffer  for  water.  Vines  two  years 
old  or  over  will  stand  very  severe  pruning  by  grasshoppers. 

HOPPER    DOZERS. 

In  alfalfa,  when  the  grasshoppers  began  to  do  damage,  they  were 
destroyed  very  successfully  by  means  of  hopper  dozers.  A  hopper 
dozer  may  be  made  in  the  form  of  a  long,  shallow  pan  of  galvanized 
iron,  placed  on   runners,  with  a   back  of  stovepipe  iron   about   3  feet 


Fig.  9.    Hopper  dozer  with  burlap  backstop  and  braced  ends. 

high.  The  pan  is  partially  filled  with  crude  oil,  a  horse  is  hitched  to 
either  end,  and  the  machine  dragged  across  the  grasshopper-infested 
field.  The  grasshoppers  jump  at  the  approach  of  the  dozer  and,  striking 
the  back  of  the  pan,  fall  into  the  oil  and  are  quickly  killed.  The  dozer 
can  be  made  of  any  convenient  length  up  to  16  or  20  feet.  The  longer 
the  dozer,  the  more  quickly  a  field  can  be  gone  over.  Where  the  check 
system  of  irrigation  is  used  and  the  checks  are  small,  a  large  dozer  can 
not  be  conveniently  used.  But  where  the  checks  are  large  and  levees 
low,  or  where  the  furrow  system  is  used,  the  longer  lengths  are  more 
desirable. 

Construction  of  a  Dozer. — For  a  dozer  16  or  20  feet  long,  a  strong 
frame  or  platform  is  necessary.  The  pan  can  be  made  in  one  piece  16 
feet  long  and  28  or  30  inches  wide,  turned  up  in  front  about  3  inches 
and  behind  about  4  or  6  inches.     Three   or  four  cross  partitions  are 


STUDIES   IN    GRASSHOPPER    CONTROL. 


15 


necessary  to  keep  the  oil  from  running  to  one  end  when  that  end  hap- 
pens to  be  lower  than  the  other,  or  the  pan  can  be  made  in  shorter 
lengths  of  the  same  width,  placed  end  to  end.  If  in  short  lengths,  lighter 
iron  can  be  used  and  consequently  will  not  cost  as  much  as  the  heavy. 
Galvanized  iron  from  No.  20  to  26  will  be  satisfactory  for  this  pan. 

In  the  construction  of  the  platform  on  which  the  pan  is  to  be  placed, 
it  should  be  borne  in  mind  that  the  closer  the  pan  is  to  the  ground  the 
more  grasshoppers  will  be  caught.  Where  several  short  pans  are  used, 
it  will  be  necessary  to  have  a  frame  into  which  they  can  be  set  and  held 
firmly.  Such  will  also  be  necessary  where  light  iron  is  used  for  a  long 
pan.  No.  20  iron  is  stiff  enough  as  that  there  is  considerable  strength 
to  it  alone,  and  it  is  not  necessary  to  have  such  a  strong  frame  as  for 


Fig.  10.    Wide  hopper  dozer  in  operation  in  alfalfa  field. 

the  lighter  iron.  At  least  five  runners  are  necessary  on  a  16-foot  dozer. 
These  can  be  made  of  old  wagon  tires,  bent  up  in  front.  Three 
of  them  should  be  turned  at  right  angles  at  the  back,  in  order  that 
uprights  may  be  fastened  to  them  that  will  hold  the  backstop.  Two-  or 
three-inch  boards  fastened  to  these  runners  will  protect  the  bottom  of 
the  pan  from  wear.  The  2  by  4  piece  in  front  must  be  very  strong;  and 
in  order  that  the  full  width  of  the  dozer  be  available,  the  ends  should 
extend  beyond  the  pan  at  least  2  feet.  A  board  at  the  back,  set  on  edge, 
will  give  additional  strength.  A  cross-piece  should  be  placed  at  the 
other  end  of  the  pan  to  hold  it  from  sliding.  The  figure  on  page  14  will 
show  the  method  of  constructing  a  very  serviceable  dozer.  It  was  found 
best  to  use  stovepipe  iron  for  the  backstop,  as  the  grasshoppers,  on 
striking  it,  would  fall  immediately  into  the  oil.  Burlap  was  used  at 
first,  but  on  striking  it  many  of  the  grasshoppers  would  cling  thereto 


16 


UNIVERSITY   OF    CALIFORNIA— EXPERIMENT    STATION. 


and  escape  without  getting  oil  enough  to  kill  them  even  though  the 
oloth  was  saturated  with  it.  A  brace  and  a  backstop  fastened  to  the 
ends  of  the  dozer  directly  behind  the  horses  will  be  found  to  improve 
the  machine. 

After  the  dozer  is  run  for  a  few  minutes,  so  many  grasshoppers  will 
be  caught  that  those  which  jump  into  the  pan  will  not  get  enough  oil 
on  them  to  kill  them.  It  will  then  be  necessary  to  clean  the  grass- 
hoppers from  the  pan.  A  good-sized  box  with  the  bottom  knocked  out 
and  a  piece  of  half-inch  mesh  wire  put  on  in  place  of  it,  will  be  found 
very  convenient  for  straining  the  oil  from  the  grasshoppers  when  they 
are  shoveled  out  of  the  pan. 

If  the  bottom  of  the  dozer  pan  is  not  well  protected,  it  will  soon  wear 
out.     It  was  found  that  with  a  good  dozer  and  a  team  of  fast-walking 


Fig.  11.    Differential  grasshopper  (Melanoplus  differentialis). 

horses,  the  grasshoppers  could  be  cleaned  out  of  a  field  to  such  an  extent 
that  the  damage  done  by  those  left  would  not  be  noticed. 

Some  species  of  grasshoppers,  being  less  active,  are  more  easily  caught. 
0.  enigma,  during  the  hot  part  of  the  day,  are  so  active  that  until  the 
wings  become  worn,  a  large  part  of  them  will  fly  over  the  backstop. 
The  best  success  in  combating  both  this  species  and  M.  uniformis  was 
had  during  the  early  morning  and  late  in  the  afternoon.  Some  days 
the  dozers  were  run  as  late  as  twelve  o'clock  at  night  with  good  success. 
Later  than  this  the  grasshoppers,  for  the  most  part,  become  so  slug- 
gish that  they  will  not  jump  at  the  approach  of  the  dozer  and  will  be 
run  over  and  not  killed.  After  going  over  a  field  one  way,  better  suc- 
cess was  had  by  going  back  over  it  in  the  opposite  direction.  When 
•grasshoppers  keep  coming  into  the  alfalfa,  it  will  be  necessary  to  use 
the  dozer  every  day;  but  usually,  after  running  over  the  field  two  or 
three  times,  so  large  a  number  will  be  caught  that  those  left  will  not  do 
great  damage. 


STUDIES   IN    GRASSHOPPER    CONTROL. 


17 


Poisoning  was  not  successful  in  the  alfalfa  fields.  Not  enough  grass- 
hoppers were  killed  to  pay  for  putting  out  the  poison.  In  such  cases 
the  alfalfa  foliage  is  preferred  to  the  poison,  and  the  grasshoppers  will 
scarcely  touch  the  latter.  Smoking  is  even  less  effective.  The  grass- 
hoppers crawl  down  among  the  stems  of  the  alfalfa  out  of  the  smoke 
and  can  scarcely  be  made  to  fly.  It  is  likely  that  enough  grasshoppers 
will  be  left  in  the  alfalfa  fields,  even  after  the  dozer  has  been  used,  so 
that  if  conditions  are  favorable  there  will  be  a  good  batch  of  eggs  the 
following  spring.  Such  being  the  case,  some  method,  such  as  disking, 
should  be  employed  to  destroy  the  eggs  which  are  deposited. 


Fig.   12. 


Differential   grasshopper  (Melanoplus 
differentialis),  young. 


THE    CAMPAIGN    AT    NEWMAN    AND    LOS    BANOS. 

The  Differential  Grasshopper  (Melanoplus  differentialis) . — This  grass- 
hopper was  practically  the  only  species  at  Newman  that  became 
abundant  enough  to  do  serious  injury.  It  actually  did,  however, 
the  most  damage  of  any  species  this  year.  The  losses  sustained  were 
chiefly  due  to  the  fact  that 
nothing  was  attempted  against 
the  pest  until  late  in  the  sea- 
son. The  country  about  New- 
man was  a  very  striking 
example  of  the  amount  of 
injury  that  a  grasshopper  is 
capable  of  doing.  A  very  con- 
servative estimate  places  the 
loss  due  to  the  work  of  this 
grasshopper  at  $10,000,  while 
some  claim  that  it  was  not  less 
than  $30,000.  These  estimates  are  based  on  the  damage  to  alfalfa  alone 
no  consideration  being  taken  of  the  injury  done  to  small  home  orchards 
and  vineyards,  and  other  less  important  crops.  (See  frontispiece,  also 
Figs.  13  and  14.)  When  it  is  understood  that  this  damage  was  done 
on  an  area  of  from  1,000  to  1,500  acres,  the  really  serious  loss  to  the 
individual  ranchers  can  be  appreciated. 

This  grasshopper  was  for  the  most  part  hatched  in  the  alfalfa  fields. 
There  had  been  some  slight  damage  done  the  previous  year,  but  not 
enough  to  cause  much  apprehension.  This  year,  however,  they  began 
to  be  noticed  as  damaging  alfalfa  about  the  first  of  June,  and  they  kept 
at  it  energetically  until  the  middle  of  August  before  they  were  under 
satisfactory  control. 

There  is  a  striking  difference  in  color  between  the  young  grasshop- 
pers and  the  adults.  This  gave  rise  to  the  belief  that  there  were  at 
least  two  different  species  concerned  in  the  work.  The  nymph,  or 
young,  is  bright  green  in  color  and  changes  slightly  with  each  succes- 


18 


UNIVERSITY    OP    CALIFORNIA  — EXPERIMENT    STATION. 


sive  moult;  and  suddenly,  when  becoming  adult,  changes  to  a  rather 
light  yellow.  This  subsequently  changes  gradually  with  most  individ- 
uals, becoming  much  darker. 

There  was  one  large  brood  produced  quite  early  in  the  summer,  but 
the  hatching  of  some  of  the  eggs  was  greatly  delayed  and  was  very 
irregular,  as  young  grasshoppers  could  be  seen  as  late  as  October. 
About  the  middle  of  July,  after  a  large  part  of  the  damage  these  grass- 
hoppers are  capable  of  doing  had  been  clone,  the  University  was 
appealed  to;  and  acting  on  the  advice  given,  many  of  the  ranchers 
began  the  use  of  hopper  dozers.  It  was  not  too  late  to  demonstrate  that- 
great  good  could  be  accomplished  by  the  use  of  the  dozers. 

In  many  fields  the  grasshoppers  were  so  thick  that  not  only  were  the 
old  leaves  and  bark  trimmed  off,  but  as  fast  as  new  growth  would  start 
that  would  be  taken  also.     In  a  few  cases  this  had  been  kept  up  so  per- 


Fig.  13.    Vineyard  defoliated  by  grasshoppers  near  Newman. 

sistently  that  the  alfalfa  was  apparently  dead.  Usually  one  could  see 
a  very  great  difference  in  a  week's  time,  after  a  field  had  been  run  over 
three  or  four  times  with  the  dozers.  In  this  way  one  or  two  cuttings 
were  obtained  from  fields  which  would  not  have  yielded  anything  had 
the  grasshoppers  been  left  alone,  and  the  alfalfa  revived  enough  to  be 
in  good  condition  to  be  pastured  during  the  fall.  This  species,  how- 
ever, is  much  more  easily  caught  in  the  dozer  than  the  species  occurring 
at  Turlock.  It  is  of  a  more  sluggish  nature  and  will  not  fly  to  as  great 
an  extent.  More  of  the  grasshoppers  would  be  run  over  by  the  dozer 
than  would  get  over  the  top  of  the  backstop. 

Poison  was  not  tried  on  this  species,  because  the  only  places  where  it 
could  have  been  used  were  the  small  orchards  adjoining  the  ranch 
buildings,  where  there  was  considerable  danger  of  stock  getting  hold  of 
either  the  bait  or  the  grasshoppers  after  they  had  eaten  poison.  There 
is  no  reason  why  the  poisoned  bran  would  not  work  very  successfully 
with  this  species,  as  it  is  a  voracious  feeder. 


STUDIES   IN    GRASSHOPPER    CONTROL. 


19 


Smoking  was  tried,  but  with  poor  success.  The  grasshoppers  would 
stir  around  a  little  when  the  smoke  first  struck  them,  but  after  becoming 
accustomed  to  it  would  pay  no  attention  whatever  to  it.  Burning 
would  have  been  a  very  good  way  of  getting  rid  of  large  numbers  of 
the  grasshoppers,  but  this  could  not  be  done  at  Newman. 

This  same  grasshopper  was  also  common  at  Los  Banos,  although  on 
the  whole  nowhere  near  as  much  damage  was  done.  They  were  not 
confined  to  one  section,  but  were  scattered  over  quite  a  considerable 
territory,  only  in  an  occasional  field  being  numerous  enough  to  do 
extensive  injury.     In  some  of  these  places  even  more  serious  damage 


Fig.  14.    Orchard  trees  from  which  leaves  and  fruit  had  been  removed  by 
grasshoppers.    Pits  shown  still  on  the  tree. 

was  done  than  at  Newman.  On  one  ranch  not  only  was  the  crop  of 
alfalfa  for  the  year  lost,  but  the  trees  around  the  house  were  stripped, 
many  being  killed.  Even  olive  and  fig  trees  were  damaged  to  a  con- 
siderable extent,  although  these  two  kinds  of  trees  were  in  most  cases 
left  alone.  Practically  nothing  was  done  against  the  grasshoppers. 
Two  different  ranchers  had  some  success  with  crude  dozers  made  out  of 
old  wooden  troughs.  But  for  the  most  part  it  was  too  late  in  the  season 
to  make  it  worth  while  to  do  anything,  after  it  was  learned  that  some- 
thing could  be  done. 

The  species  was  abundant  the  year  before  at  Dos  Palos,  doing  consid- 
erable   damage    there,    but  this  year,  with  one  exception,   there   was 


20 


UNIVERSITY    OF    CALIFORNIA— EXPERIMENT    STATION. 


scarcely  any  injury.  This  exception  was  on  one  of  the  Miller  &  Lux 
ranches,  where  a  small  vineyard  had  been  stripped  of  its  leaves  and  the 
fruit  consequently  ruined.  A  few  trees  of  an  adjoining  orchard  had 
also  been  considerably  injured.  Grasshoppers  were  quite  common  in 
other  places,  but  not  enough  so  to  do  any  noticeable  injury. 

Egg-laying. — The  egg-laying  of  Melanoplus  differentialis  is  character- 
istic of  nearly  all  grasshoppers,  and  an  account  of  the  manner  of  laying 
and  the  nature  of  the  soil  chosen  will  illustrate  how  the  danger  of  an 
infestation  the  following  year  can  be  diminished. 

Pairing  was  noticed  from  the  time  the  grasshoppers  reached  maturity 
in  June.     Eggs  large  enough  to   lay  were  found,  on  dissection,  during; 


Fig.  15.  Alfalfa  field  near  Newman  with  leaves  removed  by  grasshoppers. 
Lower  parts  of  poplar  trees  seen  in  the  background  also  defoliated  by 
these  insects. 

early  July,  but  no  grasshoppers  were  at  this  time  caught  in  the  act  of 
egg-laying,  although  there  must  have  been  some  laying  done.  None 
were  found  laying  before  active  field  observations  were  discontinued, 
about  the  middle  of  August,  but  during  the  first  week  in  October  eggs 
were  being  laid  by  thousands. 

The  insect  chooses  a  place  in  the  alfalfa  field  where  vegetation  is  not 
too  thick.  Bare  ditch  banks  or  levees  are  very  suitable  places.  The 
roadside  and  other  bare  spots  are  also  acceptable,  but  more  seemed  to 
be  laying  in  the  alfalfa  than  in  other  places.  In  some  cases  ground  was 
chosen  that  was  so  hard  a  knife  blade  could  scarcely  be  forced  into  it, 
but  much  softer  soil  was  more  usual. 

On  finding  an  acceptable  spot  the  insect  drills  a  hole  from  an  inch  to 
an  inch  and  a  half  long,  by  means  of  the  four  horn-like  points  on  the 


STUDIES   IN    GRASSHOPPER    CONTROL. 


21 


extreme  tip  of  the  abdomen.  This  hole,  as  a  rule,  is  not  put  straight 
into  the  ground,  but  at  an  angle.  About  seventy-five  were  dug  up,  and 
their  relation  to  the  position  of  the  head  of  the  insect  noted.  Of  the 
seventy-five  only  three  or  four  were  burrowed  straight  into  the  ground. 
Only  one  was  found  where  the  curve  or  angle  was  toward  the  head,  the 
position  so  commonly  figured  in  grasshopper  publications.  All  the 
remainder  had  a  decided  backward  tilt. 

As  soon  as  the  hole  is  drilled  deep  enough  so  that  nearly  the  entire 
abdomen  is  buried,  the  grasshopper  ejects  a  small  amount  of  a  frothy 
substance  into  the  bottom,  and  then  begins  to  place  the  eggs.     The 


Fig.  16.    Poplar  trees  defoliated  by  grasshoppers. 


species  does  not  seem  to  have  a  regular  manner  of  placing  the  eggs;  they 
seem  to  be  in  a  more  heterogeneous  mass  than  is  the  case  with  most 
other  species.  As  soon  as  enough  eggs  are  laid  to  fill  up  as  far  as  the 
frothy  substance  reaches,  more  of  that  is  ejected  into  the  hole.  Then 
more  eggs  are  placed,  and  so  on  until  the  hole  is  filled  within  half  an 
inch,  or  less,  of  the  top.  Most  of  this  is  filled  with  this  same  frothy 
substance.  Then,  with  the  end  of  the  abdomen,  the  grasshopper  moves 
small  pieces  of  dirt  around,  using  the  drill  as  pincers  or  claspers,  until 
the  hole  is  entirely  concealed;  then  she  walks  away. 

During  the  hot  part  of  the  day  not  less  than  two  hours  were  taken  to 
drill  the  hole  and  deposit  the  eggs.  All  the  eggs  that  have  reached  full 
development  are  placed  in  the  one  hole.    These  in  one  case  numbered  93. 


22 


UNIVERSITY    OF    CALIFORNIA— EXPERIMENT    STATION. 


Usually,  however,  there  are  considerably  less,  averaging  from  60  to  70. 
Other  layings  of  eggs  are  probably  deposited  later,  as  an  insect  killed 
just  after  finishing  egg-laying  would  show  that  the  next  lot  of  eggs  in 
the  oviduct  were  a  quarter  or  even  a  third  developed. 

The  frothy  substance  with  which  the  hole  is  lined  turns  in  a  few  hours 
into  a  hard,  cement-like  substance  that  seems  to  be  nearly  waterproof. 
The  eggs  are  thus  in  what  is  practically  a  waterproof  capsule.  Ordinary 
wettings  will  not  affect  it,  but  prolonged  soakings  may  tend  to  kill 
the  eggs. 

These  eggs  stay  in  the  capsule,  gradually  coming  to  maturity  and 
giving  up  the  young  grasshoppers  with  the  warm  days  of  spring  or  sum- 
mer. As  long  as  the  egg  capsule  remains  in  an  unbroken  condition  the 
eggs  are  pretty  well  protected;  but  if  by  some  means  it  can  be  broken, 
there  is  a  good  possibility  of  the  eggs  being  destroyed  during  the  winter. 


Fig.  17.    Wild  gourd  attacked  on  one  side  by  migrating  swarm  of  grasshoppers. 

In  certain  experiments  in  Kansas  a  number  of  years  ago,  with  which 
the  writer  was  conversant,  it  was  found  that  the  use  of  circular  and 
cut-away  disks  was  very  successful  in  breaking  up  these  capsules;  and 
it  was  observed,  furthermore,  that  instead  of  injuring  the  alfalfa,  the 
yield  of  the  alfalfa  was  actually  increased,  in  some  cases  to  the  extent 
of  a  ton  and  a  half  to  the  acre.  This  increased  yield  after  disking 
accords  with  the  experience  of  many  California  growers,  who  regularly 
disk  their  fields  each  fall.  The  practice  is  to  be  particularly  recom- 
mended wherever  grasshoppers  have  deposited  eggs.  The  blades  of  the 
disk  should  be  set  rather  straight,  so  as  not  to  tear  out  the  crown  of  the 
alfalfa  root.  The  ground  can  be  gone  over  twice,  so  as  to  checkerboard 
the  entire  field.  In  the  portion  of  the  field  next  to  the  fence,  where  grass- 
hoppers often  lay  large  quantities  of  eggs,  the  disks  should  be  run  twice 
in  opposite  directions,  and  almost  as  good  results  can  be  obtained  as  by 
crossing.  For  a  hard  soil,  the  cut-away  disk  is  the  better;  in  ordinary 
loose  soil,  the  circular  is  equally  as  satisfactory. 


STUDIES   IN    GRASSHOPPER    CONTROL.  23 


RESUME. 


This  bulletin  records  the  experience  of  a  successful  campaign  for  the 
practical  control  of  grasshoppers.  Brief  accounts  are  given  of  the 
" long-legged  grasshopper,"  the  "pale-winged  grasshopper,"  the  "devas- 
tating grasshopper,"  Hesperotettix  sp.,  and  more  detailed  data  con- 
cerning the  two  most  distinctive  forms.  The  "  valley  grasshopper"  was 
destroyed  quite  effectively  by  burning;  and,  where  this  was  not  prac- 
tical or  efficient,  by  the  use  of  poison  in  orchards  and  vineyards 
and  by  the  use  of  the  hopper  dozer  in  alfalfa  fields.  The  method  of 
constructing  a  dozer  is  given,  and  suggestions  as  to  its  use.  The 
"differential  grasshopper"  of  the  Newman  district  was  found  easily 
controllable  by  the  use  of  the  dozer;  and  no  other  methods  seemed 
desirable  under  the  conditions  obtaining  there,  except  the  use  of  the 
disk  in  fields  stocked  with  eggs. 


CALIFORNIA  PUBLICATIONS  AVAILABLE  FOR  DISTRIBUTION. 


REPORTS. 

1896.     Report    of    the    Viticultural    Work    during    the    seasons    1887-93,    with    data 

regarding  the  Vintages  of  1894-95. 
3897.     Resistant    Vines,    their    Selection,   Adaptation,    and    Grafting.      Appendix   to 

Viticultural  Report  for  1896. 
1898.     Partial   Report  of  Work  of  Agricultural  Experiment   Station  for  the  years 

1895-96  and  1896-97. 
1900.     Report  of  the  Agricultural  Experiment  Station  for  the  year  1897-98. 

1902.  Report  of  the  Agricultural  Experiment  Station  for  1898-1901. 

1903.  Report  of  the  Agricultural  Experiment  Station  for  1901-1903. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment  Station  for  1903-1904. 

BULLETINS. 

Endurance  of  Drought  in  Soils  of  the  Arid  Region. 

Report  of  the  Condition  of  Olive  Culture  in  California. 

The  Phylloxera  of  the  Vine. 

Feeding  of  Farm  Animals. 

Tolerance   of   Alkali   by   Various   Cultures. 

The  Potato- Worm  in  California. 

Pickling  Ripe  and  Green  Olives. 

Citrus  Fruit   Culture. 

Orange  and  Lemon  Rot. 

Lands  of  the  Colorado  Delta  in  Salton  Basin,  and  Supplement. 

Deciduous  Fruits  at  Paso  Robles. 

Grasshoppers  in  California. 

California    Peach-Tree    Borer. 

The  Peach-Worm. 

The  Red   Spider  of  Citrus  Trees. 

New   Methods   of  Grafting  and   Budding   Vines. 

Culture  Work  of  the  Substations. 

Resistant  Vines  and  their  Hybrids. 

California    Sugar   Industry. 

The  Value  of  Oak  Leaves  for  Forage. 

Arsenical  Insecticides. 

Fumigation  Dosage. 

Spraying  with  Distillates. 

Sulfur  Sprays  for  Red  Spider. 

Directions  for  Spraying  for  the  Codling-Moth. 

Fowl    Cholera. 

Commercial   Fertilizers. 

California  Olive  Oil ;  its  Manufacture. 

Contribution  to  the  Study  of  Fermentation. 

The  Hop  Aphis. 

Tuberculosis   in   Fowls. 

Commercial  Fertilizers. 

Pear   Scab. 

Poultry  Feeding  and  Proprietary  Foods. 

Asparagus  and  Asparagus  Rust  in  California. 

Spraying  for  Scale  Insects. 

Manufacture  of  Dry  Wines  in  Hot  Countries. 

Observations  on  Some  Vine  Diseases  in  Sonoma  County.      „ 

Tolerance  of  the  Sugar  Beet  for  Alkali. 


% 


CIRCULARS. 

No.  1.  Texas   Fever.                                         No.  10.  Reading     Course     in     Economic 

2.  Blackleg.  Entomology. 

3.  Hog  Cholera.  11.  Fumigation   Practice. 

4.  Anthrax.  12.  Silk   Culture. 

5.  Contagious  Abortion  in  Cows.  13.  The  Culture  of  the  Sugar  Beet. 
7.  Remedies  for  Insects.  14.  Practical  Suggestions  for  Cod- 
9.  Asparagus  Rust.  ling-Moth      Control      in      the 

Pajaro  Valley. 

Copies  may  be  had  by  application  to  the  Director  of  the  Experiment 
Station,  Berkeley,  California. 


I 


